Ring Gear Wear
Thread Starter
CF Veteran
Joined: Dec 2017
Posts: 1,524
Likes: 412
From: San Mateo, CA
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0 Renix, stock.
Ring Gear Wear
Here is my dana 30 Sierra 4.11 ring gear teeth. Installed 2 years ago. Do to manual locking hubs, perhaps about 800 to1200 miles of use ( actually turning) There was also a build up of fine powdery metallic sludge at bottom of the case, no chunks or metal hair, just a fine powder. oil has be drained and renewed three times in last two years
Should there be concern over the parallel wear marks along the ring gear teeth? I pulled the diff for an airlocker leak when I saw this gear wear. more photos to follow...
CF Veteran
Joined: Aug 2018
Posts: 1,905
Likes: 346
From: Idaho
Year: 89
Model: Cherokee (XJ)
Engine: Peddles
Looks good to me. Drive sides alittle towards the heel but thats ok.
Pinion kinda slides through ring hear teeth..
how much backlash do you have. backlash is to read a oil film between teeth to buffer and cushion shock and wear. Less backlash means less oil between wear areas. Atleast thats how I understand it.
Pinion kinda slides through ring hear teeth..
how much backlash do you have. backlash is to read a oil film between teeth to buffer and cushion shock and wear. Less backlash means less oil between wear areas. Atleast thats how I understand it.
Thread Starter
CF Veteran
Joined: Dec 2017
Posts: 1,524
Likes: 412
From: San Mateo, CA
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0 Renix, stock.
Thanks! Will reassemble, will rerun pattern check upon instal, and back lash too. need to replace a couple bearing shims as they got mangled upon removal.
My arb piston seal failed (bonded seal) it was one from a batch of bad seals, so they should be sending me a new one.
My arb piston seal failed (bonded seal) it was one from a batch of bad seals, so they should be sending me a new one.
CF Veteran
Joined: Jan 2017
Posts: 3,438
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
BTW I assume you changed out the rear as well. Does it have the same amount of metal sludge?
IMO those machining marks are ug-glee. I called my guy and he said they do a Micropolish to aid in break-in but it's $125.
OTOH HFT rare earth magnets are like 3 bucks a stack.
IMO those machining marks are ug-glee. I called my guy and he said they do a Micropolish to aid in break-in but it's $125.
OTOH HFT rare earth magnets are like 3 bucks a stack.
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::CF Administrator::
Joined: Feb 2011
Posts: 14,479
Likes: 805
From: Blunt, South Dakota
Year: 97
Model: Cherokee (XJ)
Engine: 4.6 stroker
Oh yeah....nothing
His pattern is close to perfect. Zero concern.
CF Veteran
Joined: Jan 2017
Posts: 3,438
Likes: 417
From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
However, note in OP's other thread
Certainly was a good deal of fine powder fine sludge in bottom, both on magnet drain plug, and filling up that valley in the casting at bottom near the cover mating edge. It appeared to just stay sludged at the bottom rather than be distributed in the oil. Usually i would expect fine hairs of metal on the magnet, not this fine powdery stuff. weird. And yes the oil was drained and refilled at least 2 or 3 times since it was rebuilt.
Maybe I guesstimate 800/1200 miles of driving with hubs locked.
So now I'm thinking "good deal of fine powder sludge" with "2 or 3 oil changes" in ~1000 miles?
While it isn't known what the exact quantity of "good deal" is note that Micropolishing is available which would significantly cut down the break-in period (and related sludge). Is it worth $250 for a set? Yeah little steep.
Anyway, if the rear diff was set up at the same time but has none of this sludge, then perhaps there is an issue in the front, unrelated to gear mesh.
CF Veteran
Joined: Jan 2017
Posts: 3,438
Likes: 417
From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Put into perspective,
is about 2 weeks for me (at least used to) with a DD. Since the OP has free wheeling hubs, I would ask first if the Sierra break-in procedure was followed:
or, the aforementioned Micropolishing should have been done if the rig was being beat to **** on the trails w/o proper break-in:
The above from detroitspeed.com. I use differentials.com myself, but I can't find a place to C&P their Micropolishing procedure.
Maybe I guesstimate 800/1200 miles of driving with hubs locked.
All new ring & pinion gear sets must be properly broken in!!!
Improper gear break-in procedures may cause overloading and overheating of the ring and pinion gears as well as break down of the gear oil. Failure to properly break-in a new gear set can be identified by inspection, and may void the manufacturer’s warranty.
If you’re replacing the ring & pinion gear set, don’t plan on heading up over that mountain pass or hooking up that heavy trailer just yet….. Following the simple steps outlined below before you head out can prevent potential noise issues or gear damage.
AGAIN, IMPROPER BREAK-IN CAN BE IDENTIFIED BY INSPECTION AND MAY VOID THE MANUFACTURER’S WARRANTY.
Improper gear break-in procedures may cause overloading and overheating of the ring and pinion gears as well as break down of the gear oil. Failure to properly break-in a new gear set can be identified by inspection, and may void the manufacturer’s warranty.
If you’re replacing the ring & pinion gear set, don’t plan on heading up over that mountain pass or hooking up that heavy trailer just yet….. Following the simple steps outlined below before you head out can prevent potential noise issues or gear damage.
- After driving lightly the first 15-20 miles at around 60 mph, STOP and let the differential cool completely. Stop & have a lunch or dinner break…..more cooling time is good. Overnight is even better.
- Maintaining a speed below 60 mph and driving conservatively for the first 100 miles is also advised.
- The gear oil should be changed after 500 miles.
- We recommend that you drive at least 500 miles before any heavy use or towing.
- During the first 45 miles of actual towing, only drive 10-15 miles at a time before stopping to let the differential cool.
AGAIN, IMPROPER BREAK-IN CAN BE IDENTIFIED BY INSPECTION AND MAY VOID THE MANUFACTURER’S WARRANTY.
GEARFX SERVICE - REM DEBURR AND MICRO POLISH - (RING & PINION GEAR)
Product Code: 070151
Many automotive components endure severe frictional forces and elevated operating temperatures. These facts are particularly evident in rear axles, where unfavorable conditions combined with the lack of proper break-in procedures lead to severe damage and efficiency losses. The ISF Process creates a smooth, micro-textured surface for enhanced oil retention properties and is metallurgically safe.
Having GearFX apply REM’s revolutionary ISF® Process creates parts that last considerably longer and perform better than standard components.
REM Isotropic Surface Finishing Part Performance Benefits:
• Quieter Operation
• Extend Component Life
• Reduce Friction and Drivetrain Loss
• Reduce Metal Debris
• Reduce Break-in Required
• Lower Operating Temperature
• Increase Efficiency
• Increase Effective Horsepower
• Increase Part Durability
• Increase Power Density
Product Code: 070151
Many automotive components endure severe frictional forces and elevated operating temperatures. These facts are particularly evident in rear axles, where unfavorable conditions combined with the lack of proper break-in procedures lead to severe damage and efficiency losses. The ISF Process creates a smooth, micro-textured surface for enhanced oil retention properties and is metallurgically safe.
Having GearFX apply REM’s revolutionary ISF® Process creates parts that last considerably longer and perform better than standard components.
REM Isotropic Surface Finishing Part Performance Benefits:
• Quieter Operation
• Extend Component Life
• Reduce Friction and Drivetrain Loss
• Reduce Metal Debris
• Reduce Break-in Required
• Lower Operating Temperature
• Increase Efficiency
• Increase Effective Horsepower
• Increase Part Durability
• Increase Power Density
Last edited by Dave51; Mar 20, 2021 at 04:53 AM.
::CF Administrator::
Joined: Feb 2011
Posts: 14,479
Likes: 805
From: Blunt, South Dakota
Year: 97
Model: Cherokee (XJ)
Engine: 4.6 stroker
Spot on, Dave
There's a reason for the break in procedure. As the new gears mesh, it generates fine particles, which is why you do a full oil change after a few hundred miles. Essentially you are micropolishing in place.
Why spend the $$$ for micropolishing, unless you're building a race car or dedicated hardcore rig
There's a reason for the break in procedure. As the new gears mesh, it generates fine particles, which is why you do a full oil change after a few hundred miles. Essentially you are micropolishing in place.
Why spend the $$$ for micropolishing, unless you're building a race car or dedicated hardcore rig
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